AND ANALOGIES, OF ROCKS. 215 



matters which are now daily deposited beneath the 

 waters of the present earth. 



If we examine the deserted seat of an inland lake, 

 we discover beds of compact mud intermixed with 

 leaves, or of mud with land shells, or of sand, or of 

 peat, or of all these, in one or more series of alter- 

 nations. Abstracting the question as it relates to 

 peat, we have here an analogy to the rocks of a coal 

 series. The mud with its plants, or shells, represents 

 the different shales and limestones ; and the sandstone 

 is the counterpart of the sand bed. The whole re- 

 quires consolidation only, to render it an ordinary 

 series of rocks. 



In sinking through the ancient sestuaries of the 

 sea, long filled up and converted into dry land, si- 

 milar beds of mud and clay, of marine shells entan- 

 gled in mud, and of sand and gravel, are found ; 

 varying in number, in thickness, in the order of repe- 

 tition, and in the quality or nature of the remains, 

 in almost every place. It is unnecessary to point 

 out more distinctly a similar analogy in these prepa- 

 rations for a series of secondary rocks ; but it ob- 

 viously requires only a repetition of the same deposits, 

 sufficiently frequent, to produce the whole series of 

 secondary strata. At what period the act of conso- 

 lidation may have taken place, we have no means of 

 knowing ; yet as far as our observations have yet 

 reached, we have no positive evidence that any ex- 

 tensive operations of this nature are now going on, 

 excepting those formerly mentioned. The process 

 may possibly be too slow to fall within the sphere of 

 our investigations. 



If the more antient strata have been formed from 

 similar materials, they should possess an analogy to 

 the secondary ; and, admitting such differences as 



